Mitsubishi Electric MDS-E, Instruction Manual

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MDS-E/EH Series Instruction Manual
6 Spindle Adjustment
327 IB-1501229-F
6.1.3 Adjusting the Acceleration/Deceleration Operation
(1) Calculating the theoretical acceleration/deceleration time
The spindle motor output characteristics (shown on the right) have three
ranges, which are constant torque, constant output, and deceleration
ranges. Each range has different calculation method. The acceleration/
deceleration time is calculated using the calculation expression which
corresponds to each range of the rotation speed for calculation. Note that
the load torque (friction torque) is not considered in the calculation
expression, so the result may slightly differ from the actual acceleration/
deceleration time.
(a) Maximum motor output during acceleration/deceleration: Po
The output during acceleration/deceleration (actual acceleration/
deceleration output) Po is 1.2-fold of "Standard output during acceleration/deceleration" or "Short time rated
output".
The output Po during acceleration/deceleration follows the expression below.
Po = ( "Short time rated output" or "Standard output during acceleration/deceleration" ) x 1.2
Substitute this value into Po of the expression.
(b) Total load inertia: J
all
Total load inertia means the total inertia of the spindle motor and of the components which are rotated the
motor (shaft, etc.).
J
all
= (Motor inertia) + (Spindle conversion inertia) [kg•m
2
]
The values obtained in (a) and (b) are substituted into the following calculation expressions.
To calculate the acceleration/deceleration time of the rotation speed N (r/min), use the expression (c), (d) or
(e) which is selected depending on the range that corresponds to the speed N.
(c) Acceleration/deceleration time for constant torque range: t1···0 to N [r/min] (0 N N1)
(For N>N1, apply N=N1 and also calculate t2 or t3.)
(d) Acceleration/deceleration time for constant output range: t2···N1 to N [r/min] (N1<N N2)
(For N>N2, apply N=N2 and also calculate t3.)
(e) Acceleration/deceleration time in deceleration output range: t3···N2 to N [r/min] (N2<N N3)
Based on the above expressions, the acceleration/deceleration time: t from 0 to N3 [r/min] is:
t = t1 + t2 + t3 [s] (Caution 2)
Out
p
ut
[
W
]
Output characteristics for
acceleration/deceleration
0 N1 N2
0
N3
Po
Rotation speed [r/min ]
Constant
output range
Constant torque range
Deceleration
range
Actual
acceleration/deceleration
output
≦ ≦
1.097 x 10
-2
x J
all
x N1 x N
t1 =
Po
[s]
(Caution 1)
≦
1.097 x 10
-2
x J
all
x (N
2
- N1
2
)
t2 =
2 x Po
[s]
(Caution 1)
≦
1.097 x 10
-2
x J
all
x (N
3
- N2
3
)
t3 =
3 x Po x N2
[s]
(Caution 1)